Y=4x^2-28x-30

Solution for Y=4x^2-28x-30 equation:

=4Y^2-28Y-30

We move all terms to the left:

-(4Y^2-28Y-30)=0

We get rid of parentheses

-4Y^2+28Y+30=0

a = -4; b = 28; c = +30;
Δ = b2-4ac
Δ = 282-4·(-4)·30
Δ = 1264
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1264}=\sqrt{16*79}=\sqrt{16}*\sqrt{79}=4\sqrt{79}$
$Y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(28)-4\sqrt{79}}{2*-4}=\frac{-28-4\sqrt{79}}{-8}
$
$Y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(28)+4\sqrt{79}}{2*-4}=\frac{-28+4\sqrt{79}}{-8}
$